CVE-2026-33157: craftcms cms Unsafe Reflection

Vulnerability summary

CVE-2026-33157 is a high (CVSS 8.6) Unsafe Reflection vulnerability in craftcms cms. EPSS estimates a 1.06% chance of exploitation in the next 30 days, higher than 63.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 24-03-2026
   PublishedVulnerability first disclosed.
2. 25-03-2026
   Last modifiedVulnerability information updated.

Description

Craft CMS is a content management system (CMS). From version 5.6.0 to before version 5.9.13, a Remote Code Execution (RCE) vulnerability exists in Craft CMS, it can be exploited by any authenticated user with control panel access. This is a bypass of a previous fix. The existing patches add cleanseConfig() to assembleLayoutFromPost() and various FieldsController actions to strip Yii2 behavior/event injection keys ("as" and "on" prefixed keys). However, the fieldLayouts parameter in ElementIndexesController::actionFilterHud() is passed directly to FieldLayout::createFromConfig() without any sanitization, enabling the same behavior injection attack chain. This issue has been patched in version 5.9.13.

• CWE-470Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.